There's been several times I've seen dehydrated looking snakes in CA deserts crossing the road and I tend to think dehydration can be a significant source(or at least contributing factor) of mortality in dry years.

The worst was once during a drought in TX I saw a Coachwhip that was apparently stalking a bird that had just been hit by a car and this Coachwhip was so dehydrated and weak it could barely hold it's head up.

On a lighter note, somebody sent me a photo a few years ago of a wild grayband drinking water off somebody's porch steps during a rainstorm.-----www.hcu-tx.org/